AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 4 665-R675, Copyright © 1986 by American Physiological Society
Physical and metabolic correlates of sexual inactivity in aged male mice
F. H. Bronson and C. Desjardins
The object of this study was to identify specific syndromes of sexual loss
in aged male mice. Emphasis was placed on uncovering syndromes that involve
physical as opposed to motivational deterioration. To this end, 30-mo-old
CBF1 male mice were subjected to a large battery of tests, each of which
was designed to detect sensory, neuromuscular, metabolic, or sexual
deficits. Over 50 measures were obtained on each of 63 males. A group of 23
6-mo-old males were studied simultaneously to establish base lines of
normal performance. Old males routinely showed evidence of deterioration in
some tests but not in others. Some old males actually performed as well as
young males in some tests, including an exhaustive test of sexual capacity.
Ten nonsexual measures were significantly correlated with sexual activity.
Further analyses then suggested seven distinct syndromes of reproductive
loss, each with its own specific cause and unique manifestation. Six of
these syndromes manifested themselves as behavioral deficits; one was
related to a failure to eject sperm. Our data also suggest the possible
existence of two more syndromes, but these remain to be verified more
fully. Although additional syndromes undoubtedly will be found in male
mice, the present testing paradigm can be exploited to isolate and study
the functional bases of each of these specific facets of reproductive loss.
